This invention relates generally to methods for estimating the minimal noise figure for a wideband amplifier. More specifically, but without limitation thereto, the invention relates to a computer program that computes the greatest lower bound of the noise figure that exists uniformly over the operating band of a given amplifier utilizing a loss-less matching network.
A common problem in electrical engineering is the amplification of a signal. Aside from increasing the power level of the signal, a common goal in the design of an amplifier is to minimize the noise in the amplified signal. The parameter describing the noise contributed by the amplifier is known as the “noise figure” (F). For any given amplifier, F can be defined as “the ratio of the available signal-to-noise power ratio at the input to the available signal-to-noise power ratio at the output”. (G. Gonzalez, “Microwave Transistor Amplifiers”, page 296, Second Edition)
To improve the performance of a two-port amplifier, a “matching” network connecting a signal generator to the amplifier may be used. Ideally, the matching networks can simultaneously maximize transducer power gain and minimize the F of the amplifier while maintaining stability. In practice, maximizing gain and minimizing F are competing objectives. If the signal is narrowband, standard methods allow a matching network to realize the minimum F. If however the signal is wideband, there are no known methods that minimize F uniformly over the operating band.
There is a need in the art to be able to ascertain, for a given wideband amplifier, the greatest lower bound of the noise figure that pertains uniformly over the operating band of the amplifier.